1. Field of the Invention
The invention relates to a corrugating machine, comprising a device for quality assessment of the adhesive bond between the various webs of material.
2. Background Art
GB2 369 186 A describes an apparatus for continuously checking the quality of a web of corrugated board produced in a corrugating machine. To this end, tire moved web of corrugated board is provided with a mechanical vibration sensor which is set vibrating upon conveyance of the web of corrugated board. The kind of vibrations suggests the quality of the adhesive bond. Drawbacks reside in that the sensor is in permanent mechanical contact with the web of corrugated board, giving rise to wear on both parts. Moreover, the mechanical inertia of the sensor complicates the examination of the web of corrugated board at high conveying velocities of, for example, 400 m/min.
DE 199 55 917 A1 also teaches a corrugating machine with a quality assessment device. Optical distance sensors are provided on both sides of a web of single-faced corrugated board so that the precise course of the corrugated medium can be computed from the assessed data. To this end, enormous quantities of data must be processed. Column 3, line 31f, fundamentally mentions that, in lieu of the laser sensors used for distance measurement, corresponding ultrasonic sensors may be used for ultrasonic scanning of the corrugated medium. It is not said how this is handled in detail. In this case too, what is determined are the distances of the outside of the web of corrugated board from the sensors so that again great quantities of data will have to be processed.